Boat drain

Abstract

An automatic boat drain for siphoning water from the interior of a boat, the drain including a flow tube secured to the exterior of the boat transom with the inlet end of the flow tube being below the water surface and oriented so that water is forced to flow through the flow tube as the boat moves forward above a minimum speed, the outlet end of the flow tube being above the water surface, an entraining tube having the inlet end adjacent the interior bottom of the boat, and a venturi forming connection positioned above the water surface connecting the entraining tube outlet end to the flow tube adjacent to and spaced from the flow tube outlet end whereby as the boat moves through water the flow of water forced through the flow tube will produce a venturi effect to drain water from the boat interior while the venturi positioned above the water surface prevents the possibility of water being siphoning into the boat.

What is claimed is: 
     
       1. For use with a boat having a bow end and a stern end, the stern end being formed by a transom having an interior and an exterior surface and an upper edge, an automatic drain for automatically siphoning water from the boat interior when the boat moves forward through water at or above a minimum speed, the automatic drain comprising: a flow tube secured to the exterior surface of the boat transom, the flow tube having an inlet and outlet end, the inlet end extending below the water surface and under the boat immediately forward of the transom, and being open in the direction towards the boat bow end, the flow tube having the outlet end above the water surface;   an entraining tube substantially contained within the interior of the boat and having an inlet end and an outlet end, the inlet end being positioned adjacent the interior bottom of the boat; and   a venturi forming connection positioned at the top of the transom upper edge and between said entraining tube outlet end and said flow tube adjacent to and spaced from said flow tube outlet end, whereby no part of the drain is required to penetrate the boat.   
     
     
       2. A drain for automatically siphoning water from a boat according to claim 1 wnerein said venturi connection is formed by means of an increase in internal diameter of said flow tube in the direction towards said outlet end, said outlet end of said entraining tube being connected to said increased diameter portion of said flow tube adjacent the point of diameter increase. 
     
     
       3. For use with a boat having a bow end and a stern end, the stern end being formed by a transom having an interior and an exterior surface and having a small diameter opening through the transom adjacent the bottom of the boat, an automatic drain for automatically siphoning water from the boat interior when the boat moves forward through water at or above a minimum speed, the automatic drain comprising: a flow tube secured to the exterior surface of the boat transom, the flow tube having an inlet and outlet end, the inlet end extending below the water surface, and being open in the direction towards the boat bow end, the flow tube having an outlet end above the water surface;   an entraining tube secured to the exterior surface of the boat transom and having an inlet end and an outlet end, the inlet end portion extending through the opening in the boat transom, the inlet end being positioned within the boat and adjacent the interior bottom of the boat; and   a venturi forming connection positioned above the water surface and between said entraining tube outlet end and said flow tube adjacent to and spaced from said flow tube outlet end, and being secured to the exterior surface of the boat transom.